Chemical structure representations have been evolving over the past several decades, leading to many advances in chemical informatics. Depending on the format used, chemists can quickly perform exact structure, sub-structure and similar structure queries against a collection of chemicals. Currently, there are dozens of ways to represent chemical structures for machine use. These formats vary in complexity, detail, and value. However, most chemical representations are proprietary and solutions built around them can be expensive. Some of the more common chemical file formats useful with computer analysis are SMILES (Simplified Molecular Input Line Entry System) and Connection Table Files, but the search engines employed with these formats can be difficult to work with. The IUPAC (International Union of Pure and Applied Chemistry) International Chemical Identifier (InChI) is an open system for generating unique string representations of chemical compounds, but there is currently no search engine that can directly search InChI strings (“InChIs”) to determine chemical similarity.